The invention is directed vascular medical procedures using catheters and/or guide wires.
The state of the art in cardiovascular, and vascular procedures in general, is at the forefront of interventional medicine procedures designed to prolong life and add to the quality of life. Interventional medicine, whether performed by an interventionalist specialist or other practitioner, is an advancing and beneficial science. For many people, a healthy and sustained existence is in constant jeopardy due to clogged, narrowed, sclerosed or damaged vasculature. This is especially true of the cardiovasculature and peripheral vasculature. Interventional medicine is designed to address these and other problems.
Commonly, a vessel may become stenotic, or narrowed. One of the most familiar and common etiologies of this stenosis is atherosclerosis. Atherosclerosis is a thickening and hardening of medium and larger arteries with narrowing of the arterial lumen by atherosclerotic plaques; its cause is multifactorial. See, Andreoli, Carpenter, Plum and Smith, Cecil, Essentials of Medicine (W. B. Saunders Co. 1986). Other causes of stenosis include injury, syphilis, polyarteritis nodosa, Takayasu""s disease, disseminated lupus erythematous, rheumatoid arthritis and other arteritis. Id. There is also continuing evidence that timely Percutaneous Transluminal Coronary Angioplasty (PTCA) is superior to other treatments in patients with acute myocardial infarction. See, Sutsch, Amamn, To Stent or Not to Stent, Schweiz. Med. Wochenchr. 1999;
Blood flow volume through a stenotic vessel is slowed and restricted or xe2x80x9cbacked upxe2x80x9d proximal to the stenosis. This can be further complicated by mechanical, chemical and immunologic injury. The intimal surface of the vessel may ulcerate, thrombose and occlude the lumen of the vessel. This leads to decreased nourishment and oxygenation of the distal tissues and can ultimately lead to necrosis.
Further, and consistent with Bernoulli""s law, the velocity of the blood flow is inversely proportional to the pressure exerted by the side of the vessel. In other words, the velocity is greatest and the pressure is lowest at the point of maximum stenosis. This fact has important ramifications as the increased velocity leads to increase turbulence in the flow distal to the stenosis. This, in turn, increases the ability of deposits, i.e. atherosclerotic plaques, to adhere to the vascular intima. In a similar phenomenon, plaques tend to occur at arterial bifurcations, again due to the turbulent flow in the area. The phenomenon is routine at branch sites, i.e. bifurcation and trifurcation of vessels or any multiple branching of a vessel. A common site of bifurcation of vessels is in the coronary vascular anatomy.
It is well known that the coronary arteries are markedly susceptible to atherosclerosis. This is especially true within the first six centimeters of origin of the vessel. Additionally, coronary arteries have multiple bifurcations. For example, the right and left coronary arteries bifurcate and branch as they descend the myocardium. Common sites for stenosis include the left coronary artery bifurcation to the circumflex and anterior interventricular (descending) artery; right coronary artery to the posterior interventricular and right marginal arteries; and bifurcations associated with the crux and marginal arteries. Further, any vessel of the body that suffers the effects of atherosclerosis can stenose and become a candidate for treatment, particularly in the peripheral vessels.
Treatment mechanisms for stenotic vessels have range from and include chemotherapy, radiation, Coronary Artery Bypass Grafting (CABG), angioplasty, rotational cutting devices to remove plaque formation and laser treatments. Each treatment has individual indications and contraindications. Additionally, each treatment modality has its own attendant risks. CABG of blocked or stenotic vessels is the least conservative, most expensive, most painful and is attended by the most serious complications. Surgery also requires the longest convalescence. See, Sutsch, Amamn, To Stent or Not to Stent, Schweiz. Med. Wochenchr. 1999; 129:1979-96. Chemotherapy and radiation treatment both have unwanted side effects. Currently, one of the safest and most effective treatments of stenotic vessels is percutaneous angioplasty. A common example of this is PTCA.
In the procedure, considered a non surgical interventional radiological procedure, a balloon catheter is placed in a diseased vessel through a small incision in to a main vessel; the femoral artery, for example. The catheter is tipped with a balloon at the end which can be inflated within the stenotic vessel to make the vessel patent. In order to guide the catheter to the diseased vessel and its stenosed portion, the catheter is placed over a steerable guide wire.
Inflation of the balloon is often all that is needed to make the stenotic vessel patent, but more often a stent is used to maintain patency of the vessel. A stent is a type of intra-vascular medical device used to maintain a bodily orifice or cavity after placement. Usually, a stent is comprised of an interconnected mesh of non-absorbable surgical grade material that, after placement, lies within the lumen of tubular structures and is used to provide support. Very commonly, a stent is used after dilation of an atherosclerotic coronary or peripheral vessel with a balloon catheter.
PTCA, with or without stent deployment, is performed commonly all over the world. Multiple vessels throughout the anatomy are treated. See, Sutsch, Amamn, To Stent or Not to Stent, Schweiz. Med. Wochenchr. 1999; 129:1979-96; Tan, Lim, What you Need to Knowxe2x80x94Coronary Stentingxe2x80x94What""s New in the Horizon, Singapore Med. J. 1999; Vol. 40(06). Treatment of bifurcation lesions is also common. See, Holmes et al., Coronary Artery Stents, JACC Vol. 32 No. 5, 1998:1471-82. Treatment of bifurcation lesions is associated with increased early complications including compromise of either the branch vessel (the vessel off the main or parent vessel) or the target lesion (usually the lesion in the parent vessel) and increased potential for restenosis because of inadequate initial results. Stenting has an additional potential problem in that it may impair access to the side branch.
Current practices for improving access to ostial lesions, elongated lesions, bifurcating lesions and other difficult to treat stenoses include multiple guide wires. The use of multiple guide wires can become entangled in the guiding catheter or within the vessel. Many procedures need to be aborted or delayed if the wires become hopelessly entangled; some cases are then moved to open heart surgery due to loss of stents in the coronary vessel or coronary occlusion from dissection. To maintain side branch access, xe2x80x9cjailing guide wire techniquexe2x80x9d has been used in the past where the wire to the side branch artery is pinned between the stent and the vessel wall. If the jailed wire to the side branch artery is not needed, the wire is then removed and the stent further dilated. In addition to jailing the wire, there is also xe2x80x9cjailing of the side branch artery access or originxe2x80x9d by the placement of stent across a bifurcating stenosis or a stenosis very close to a side branch artery. However, there is no guide wire in the side branch. But the opening of the side branch is covered with the stent. The side branch opening may be compromised by the struts of the stent, plaque shifting into the side branch or compression. These unwanted effects may acutely close the side branch manifesting as an acute myocardial infarction or later as restenosis from neointimal hyperplasia causing restriction in blood flow or ischemia. Treatment of the side branch next to the stenosis has been recognized as technically challenging for interventionalists as well as to patients. One goal of the current invention is to help eliminate and avoid these challenges.
Given the foregoing, a method and apparatus to avoid entanglement of guide wires, damage to vessels and better access to branch vessels will be a further advancement in the area of interventional procedures.
The present invention is directed to a method and apparatus for use in interventional medicine; particularly in multiple branch lesions located in the coronary and peripheral vasculature. The invention consists of a sheath containing single or multiple exitable lumens for the guidance of medical devices used in interventional medicine. The invention consists of exitable lumen guide wire sheaths wherein each sheath contains individually compartmentalized exitable lumens; each walled off from the other and each containing a mode of exit for the wire. Separation of the wires during that portion of the procedure prior to deployment of the stent or inflation of the balloon eliminates the risk of entanglement of multiple wires. A method for accomplishing this is introduced using the present invention to separate the wires prior to deployment and dilation of a balloon and stent or other selected intra-vascular medical device.
Each walled off lumen becomes a channel for travel of an individual guide wire. The first end of the sheath is located at the proximal portion, that portion that remains within the hands of the interventionalist or other practitioner. The first end of the sheath contains a feeder portion of greater durometer than the rest of the sheath. The feeder portion will have a channel corresponding to each individually compartmentalized lumen. The feeder portion will have an exitable portion along its length for the initial separation of a selected guide wire. The distal part of the exitable lumen guide wire sheath, that portion introduced percutaneously to the target lesion, is more flexible than the first end. In one preferred embodiment, the wall of the lumen can be opened along its length. In this way, a first selected guide wire may exit the sheath as a balloon and stent are advanced along its length or the sheath may be easily removed without losing wire position. The first selected guide wire is able to completely exit the individually compartmentalized exitable lumen as the end of the particular compartment may be selectively closed off at its distal end. Once the first selected wire and balloon are free of the sheath, the interventionalist or other practitioner may inflate and enlarge the stenotic lumen with the stent in a desired location. In another preferred embodiment, the distal second end of a selected exitable lumen of the exitable lumen guide wire sheath may be closed off and be distal to a pre-selected opening for directional advancement of a guide wire.
The first selected guide wire, having performed its function, allows for a second selected guide wire to be used without the risk of entanglement of the wires. The selected procedure may continue with additional guide wires without the risk of entanglement.
Other embodiments of the invention include differing fabrications of the wall of the individually compartmentalized lumens. Preferably, the design is directed to an ease of separation of the wire from the individually compartmentalized lumen. Scoring, weakening, fenestrating, and mold rolling the wall of the lumen are examples of such designs. This may be mounted, attached or fused to catheter balloon design(s).